Preheat oven to 350°F. Line cupcake pan with liners and set aside.
In bowl of an electric mixer whisk the flour, sugar, cocoa powder, baking soda, baking powder, and salt.
In a large liquid measuring cup whisk the egg, buttermilk, hot water (or coffee), oil and vanilla.
Add wet ingredients to the dry ingredients and mix on medium speed for 2 minutes. Scrape the sides of the bowl with a spatula and mix for another 30 seconds.
Scoop (pour) the batter into the cupcake liners, the batter is very very thin, filling only halfway full, or up to 2/3 full but no more!
Bake for 13-16 minutes or until a toothpick inserted in the center comes out with moist crumbs. **
Remove from the oven and allow cupcakes to cool in pan for 10 minutes. Transfer to wire rack to cool completely.
Coconut Pecan Frosting
In a saucepan whisk the cream sugar, egg yolks, and salt. Cook over medium heat, stirring occassionally. Bring to a low simmer and cook until thickened. Remove from heat and add the butter, vanilla, toasted coconut and pecans. Set aside to cool to room temperature.
Whipped Chocolate Mousse
With the whisk attachment, whip the butter on medium speed for 4 minutes.
Reduce speed and slowly add the powdered sugar. Once combined add the vanilla and melted chocolate. Whip at medium-high speed for 1 minute. Add the heavy cream and whip for another 1-2 minutes or until light and fluffy. Scrape down the sides of the bowl and whip for another 30 seconds.
Place the frosting/mousse in a piping bag.
Remove the center of the cupcakes with a cupcake corer***. Fill the centers with the chocolate mousse. Spoon a generous amount of coconut pecan frosting overtop of each cupcake. Enjoy!
I've made this frosting without toasting the coconut and it's not the same. It's definitely worth it to toast the coconut.
**My cupcakes baked for 14-15 minutes. If your oven temperature is a bit off, you may have to bake them longer, about 18 minutes. Check the cupcakes to make sure you don't over bake them. Over baking cake will make it dry.
***If you don't have a cupcake corer (I don't), use a large piping tip. While pushing down into the center of the cupcake, rotate the piping tip, turning it until it reaches halfway through the cupcake. Pull the piping tip out and you'll have successfully removed the cupcake core.
Store cupcakes in the fridge. Will last in fridge for 3-4 days. Mine never last past 1 day... we devour these!